WASHINGTON (CNN) -- A U.S. soldier convicted of rape and murder two decades ago will be executed December 10 in the nation's first military execution since 1961, the Army said Thursday.

Pvt. Ronald Gray has been on the military's death row at Fort Leavenworth, Kansas, since 1988. A court-martial panel sitting at Fort Bragg, North Carolina, unanimously convicted him of committing two murders and other crimes in the Fayetteville, North Carolina, area, and sentenced him to death.

Gray's execution by injection will be carried out by Fort Leavenworth soldiers at the Federal Correctional Complex in Terre Haute, Indiana, the Army said in a news release.

Gray was convicted of raping and killing a female Army private and a civilian near his post at Fort Bragg. He was also convicted of the rape and attempted murder of another fellow soldier in her barracks at the post.

Both military and civilian courts found Gray responsible for the crimes, which were committed between April 1986 and January 1987. Gray pleaded guilty to two murders and five rapes in a civilian court and was sentenced to three consecutive and five concurrent life terms.

The general court-martial at Fort Bragg then tried him and in April 1988 convicted him of two murders, an attempted murder and three rapes.

In July, President George W. Bush approved the Army's request to execute Gray.

"The president took action following completion of a full appellate process, which upheld the conviction and sentence to death," the Army said in the news release. "Two petitions to the U.S. Supreme Court were denied during the appellate processing of Pvt. Gray's case."

Members of the U.S. military have been executed throughout history, but just 10 have been executed with presidential approval since 1951 under the Uniform Code of Military Justice, the military's modern-day legal system.

The Army also sought Bush's authorization to execute another condemned soldier, Pvt. Dwight Loving, who was convicted of robbing and killing two cab drivers in 1988.

The last U.S. military execution was in 1961, when Army Pvt. John Bennett was hanged for raping and attempting to kill an 11-year-old Austrian girl. Bennett was sentenced in 1955.

The U.S. military hasn't actively pursued an execution for a military prisoner since President John F. Kennedy commuted a death sentence in 1962. Nine men are on military death row.